ISAM files are used as ordinary files. They are not synchronized with OpenTP1 transaction processing.

This facility allows the use of ISAM files in synchronization with transaction processing. If ISAM is used with ISAM/B, file integrity will be assured through transaction commitment/rollback.

(a) Products prerequisite to ISAM/B

Before ISAM files can be used with ISAM/B, the ISAM transaction facility (ISAM/B) must be available in addition to ISAM.

(b) Area for file creation

ISAM files to be used with ISAM/B must be created in the area allocated for the OpenTP1 file system.

(c) Difference from OpenTP1 file service (TP1/FS/xxx)

ISAM/B does not use the lock service. Therefore, even when a deadlock occurs, the OpenTP1 lock service facility (such as lock scope reduction based on priority and deadlock information output) is not available.

The figure below shows the form of ISAM file services.

Figure 4-22 Form of ISAM file services